My “summer best” full-sus is pretty much unused during the cold, wet months, but do I need to do anything to winterise the tubeless set-up? Is it worth deflating the tyres and emptying out sealant, or just leave it alone and deal with it in the Spring? Or give the wheels a spin every few weeks maybe?

I know using it is an option, but I can’t be arsed with the cleaning, and the hardtail likes the mud better…

do nothing.

Except top it up in spring.

I’ve just changed a tyre that was last topped up with sealant at the beginning of the summer, I was surprised how liquid the sealant was.

I half expected to find a gooey mess. So I vote for leave it and put a bit more in when you dig it out after winter.

Let somebody else ride it for winter..

Rig up solar panel to butchered turbo-trainer plus rollers so it slowly drives the wheels round constantly. Like a watch winder, for a bike.

As above – do nothing. I used to leave tubeless tyres for six months, over the winter in Greece while I was in the “grim north”, and other than leaving them with slightly higher air pressure (30 psi or something like that) I did nothing special to them and they just needed the pressure topping up in late spring, when I returned.
Non ever lost enough pressure to break the rim seal.

It’s summer when tubeless goes off quickest. But I wouldn’t do anything then either!

My “summer best” full-sus is pretty much unused during the cold, wet months

Bizarre, having a bike for a couple of months of the year?.